Open AccessCyclostrophic winds from the Visible and Infrared Thermal Imaging Spectrometer temperature sounding: A preliminary analysis
Author(s) -
Piccialli A.,
Titov D. V.,
Grassi D.,
Khatuntsev I.,
Drossart P.,
Piccioni G.,
Migliorini A.
Publication year - 2008
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2008je003127
Subject(s) - venus , depth sounding , atmospheric sciences , atmosphere of venus , thermosphere , middle latitudes , atmosphere (unit) , wind speed , geology , jet (fluid) , infrared , spectrometer , latitude , physics , environmental science , geophysics , meteorology , ionosphere , astronomy , geodesy , astrobiology , optics , oceanography , thermodynamics
Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) onboard the Venus Express spacecraft has been operating since April 2006 providing new observations of the temperature structure of Venus mesosphere (60–95 km). Zonal winds in the middle atmosphere of Venus have been retrieved from VIRTIS temperature profiles using the cyclostrophic approximation. The wind field is characterized by three main features: (1) a midlatitude jet connected to the thermal feature known as the cold collar; the jet reaches a maximum speed of 80–90 ± 10 m/s near the cloud top (∼70 km altitude) at 50°S latitude; (2) a strong decrease of wind from 60°S toward the pole reaching zero velocity at ∼70°S; and (3) the decrease of the wind above the jet with increasing altitude. Local time dependence of the temperature and wind field has been analyzed. Temperatures show at cloud tops a cooling of ∼15 K during the night which propagates also on the zonal wind field. Comparison with cloud‐tracked winds from Venus Monitoring Camera images indicates a first‐order agreement.